1. Field of the Invention
The present invention relates to a color picture display apparatus and, particularly, to a system of signal application to color picture elements of a color display apparatus of matrix-drive type.
2. Description of the Prior Art
FIG. 1 shows an example of the conventional matrix-drive type color picture display apparatus. In the figure, symbols R, G and B represent three kinds of picture elements which are emissive in red, green and blue, respectively, in response to respective signals applied thereto. Each picture element is formed of coloring material such as an emissive layer of a light emitting diode layer, electric field emissive layer, plasma emissive layer or fluorescent emissive layer, or a non-emissive layer such as a liquid crystal layer, electrochromic layer or PLZT layer. A red picture element, a green picture element and a blue picture element in combination constitute a unit picture element, and a number of unit picture elements are disposed in a two-dimensional space to form a matrix-drive type color picture display panel.
A system of signal application to the unit picture elements for displaying a television picture will first be described using video signal waveforms shown in FIG. 2. In FIG. 2, video signals A1, A2, . . . , and Aj are used to form an odd numbered field, while video signals B1, B2, . . . , and Bj are used to form an even numbered field. The negative pulse located at the left end of each video signal is the horizontal synchronizing pulse in the television signal.
First, a set of three-color information is sampled at a timing of A1-1 in the video signal A1, and drive signals for each color are produced through the signal conversion and applied to red, green and blue picture elements of a unit driving picture element 1-1. Subsequently, at a timing of A1-2, another video information is sampled and the corresponding drive signals are applied to a unit driving picture element 1-2. In this way the video signal A1 is applied to a series of unit driving picture elements. In summary, video signals Aj are applied to unit driving picture elements j-i, where 1.ltoreq.j&lt;M and 1.ltoreq.i&lt;N.
Following the odd numbered field, video information is sampled in video signals Bj for the even numbered field at timings Bj-i, and the corresponding signals are applied to unit driving picture elements j-i, where 1.ltoreq.j&lt;M and 1.ltoreq.i&lt;N.
The foregoing conventional system has a drawback of low resolution, since the resolution of displayed picture is determined by the unit picture element which needs three color picture elements.
To display a television picture clearly, the display apparatus needs to have a performance of high resolution, and one system of attaining this is to increase the number of picture elements in the horizontal direction. However, the increase in the number of horizontal picture elements results in the following disadvantages.
(1) The number of external connections increases in proportion to the increase in the horizontal picture elements, causing an increased packaging cost and lowered reliability of connection.
(2) Increase in the number of picture elements for a fixed panel size needs the reduction in the size of picture element, and the lowered aperture factor causes the reduction in the display intensity and thus the degraded picture quality.
(3) The increased distance between adjacent picture elements causes the increased electrical leakage at the spacing, resulting in a lowered yield of display panel and thus in the increased production cost.
In order to overcome the foregoing deficiencies, there has been proposed a system of improving the resolution through the formation of a unit displaying picture element using one red picture element, one blue picture element and two green picture elements, instead of using red, blue and green picture elements.